1. Field of the Invention
The present invention relates to a moving mechanism and, more particularly, to a moving mechanism optimal for a moving system for use in a shuttle and the like moving between industrial robots or NC machine tools and requiring a precise linear motion.
2. Related Background Art
Examples of a moving mechanism for use in machines of this type are a mechanism in which a rod member is sandwiched and moved by a combination of a plurality of friction rollers as disclosed in Japanese Patent Laid-Open No. 61-117043, and a mechanism in which a nut member threadably engaged with a ball bearing screw is mounted on a moving member side and the ball screw is rotated to move the moving body along the ball screw.
As a feed apparatus of a machine tool, apparatuses for friction-driving a moving body along a guide bar by using friction rollers are disclosed in Japanese Patent Publication No. 58-54948 and Japanese Patent Laid-Open No. 61-230835. In addition, a device according to the prior application of the present inventor is disclosed in Japanese Utility Model Application No. 62-113867.
Japanese Patent Laid-Open No. 63-132316 is a prior art reference concerning a countermeasure against sliding of a friction-driving apparatus. This patent specification discloses a friction-driving apparatus comprising a slider, a driving roller, abutting against the slider, for driving it by a friction, an adjusting mechanism for adjusting an abutting force between the slider and the driving roller, a speed detector for detecting a moving speed of the slider, a rotational speed detector for detecting a rotational speed of the driving roller, and a controller for arithmetically processing signals from the speed detector and the rotational speed detector, and controlling the adjusting mechanism on the basis of a difference signal.
Japanese Patent Laid-Open No. 63-132317 as a related patent application discloses a friction-driving apparatus comprising a slider, a driving roller, abutting against the slider, for driving it by a friction, an adjusting mechanism for adjusting an abutting force between the slider and the driving roller, a displacement detector for detecting a displacement of the slider, a rotational angle detector for detecting rotational angle of the driving roller, and a controller for arithmetically processing signals from the displacement detector and the rotational angle detector to calculate a displacement between the driving roller and the slider, and controlling the adjusting mechanism on the basis of a difference signal.